This project is designed to determine if intestinal lactobacilli affect the level of serum cholesterol and lipoproteins in pigs on normal and cholesterogenic diets. Weaned pigs will be fed the regular and the American swine diet, with each diet also tested by supplementation with Lactobacillus acidophilus. The four groups of pigs are to be examined periodically for levels of serum cholesterol and lipoproteins. The lactobacillus supplement will be a pig isolate, prepared to have maximum viability and minimum injury prior to being fed. The experimental protocol was designed to evaluate the lactobacillus supplement to produce pork with lowered cholesterol and lipoprotein. The American swine diet is expected to evaluate the lactobacillus supplement for possible reduction of serum cholesterol and lipoproteins in humans. Subsequent phases of research are planned for determining the optimum time for feeding lactobacillus supplements to pigs for the production of human foods. The study is expected to provide the basis for the selection of cultures for future use as dietary supplements for human and animal feeding, as well as the basis for designing facilities required for the production of cultures for routine supplementation of animal and human diets.